In the middle of the morning, she'd indulge her first craving of the day with a trip to the office refrigerator to grab one of the free sodas her company supplied. Coca-Cola, Pepsi, Mountain Dew, cherry soda--it didn't matter, she was an equal-opportunity drinker. In the afternoon, she'd snatch another can, and dinner often meant a third. "If I wasn't drinking soda, I was thinking about it," says Arndt, a corporate consultant who lives in Grafton, WI.

Her weight problems began at age 10, not long after she started drinking large amounts of pop, and continued into her 20s and 30s. At her peak, she weighed 314 pounds. In addition to feeling heavy and out of shape, she dealt with rampant cavities, frequent mood swings, and erratic energy levels. "I'd get lethargic midmorning, so I'd grab a soda, thinking it would give me a pick-me-up. I'd be a little hyper, but then half an hour later, I would practically be asleep at my keyboard."

Arndt's passion for pop is all too familiar to the average American--who drinks 18 ounces, or two full glasses, of soft drinks a day. In fact, according to a study last year, soda and other sugar-sweetened drinks have become the largest source of calories in the American diet, replacing white bread. The proliferation of soda tells the story: 450 different varieties are sold in the United States. While soft drinks are still king, with sales reaching $68.1 billion in 2005, sports drinks sales have increased 19.3% over the past year to $1.5 billion.

People may think they're doing something healthy "by grabbing a bottle of Powerade instead of a can of Coke," says Kara Gallagher, PhD, an assistant professor of exercise physiology at the University of Louisville and a Prevention advisor. But at 10 calories per ounce, that Powerade is almost as bad as a can of Coke, which has 12 per ounce. "Unless you're exercising vigorously, you don't need sports drinks. They have a lot of empty calories, just like anything else," she says.

Most people would agree that their love affair with the sweet stuff--whatever flavor it might be--isn't all that healthy, but no one would put it in the same class as a truly bad habit such as smoking or drinking alcohol to excess, right?

Wrong. Scientists are beginning to do just that. The bulk of the research has focused on connecting the dots between consumption of sugar-sweetened beverages and weight gain, but there is mounting evidence that our national obsession with liquid candy affects more than just our figures. From the very first sip, experts say, cola starts to wreak havoc on the body. It corrodes the teeth, confuses the appetite-regulating hormones in the digestive tract, attacks the bones, and encourages the organ breakdown that leads to diabetes.

Arndt, for one, is convinced that soda was the primary cause of her problems: "I tried to eat somewhat healthy, but my doctors weren't happy about how much I drank, and they attributed my weight, in part, to that. And going to the dentist was never fun. The dentist would always say, 'Lay off the soda.'" In December 2005, she made the decision to get healthy. With the help of Jenny Craig and Curves, she licked her soda habit and lost 90 pounds in 7 months.

"I feel incredible," she says.

It's time for us all to follow Arndt's lead. The latest research can't be any clearer: When it comes to your health, drinking soda is playing a startling number of dangerous roles, starting with... [pagebreak]

Stop Drinking Soda Reason #1: Waist Widener

Sweetened drinks can pack on the pounds. If, on average, we're drinking 18 ounces of liquid candy daily, we're adding about 225 calories to our diet. Over the course of a month, that's almost 7,000 additional calories, which can easily translate to a 2-pound gain. Over a year, these drinks could be adding 24 pounds to our bottom line.

That seems to be just what's happening: Over the past 4 decades, our increasing consumption of soda has been matched by our ever-expanding waistlines. "In my estimation, sugary beverages are one of the two leading environmental causes of obesity, perhaps second only to TV viewing in the magnitude of its effect," says David S. Ludwig, MD, PhD, director of the obesity program at Children's Hospital Boston.

He and colleagues at the Harvard School of Public Health presented the first strong evidence linking soft drink consumption to childhood obesity back in 2001. They tracked the diets of 548 teens for 19 months and found that kids who drank sugar-sweetened beverages regularly were more likely to be overweight than those who didn't. The researchers also found that the odds of becoming obese increased 60% for each can or glass a day of sugar-sweetened soft drinks.

Ludwig followed up with an intervention study, published earlier this year, examining 103 students from a Cambridge, MA, high school for 6 months. Half were instructed to drink whatever they liked. The other half were asked to stop drinking sugar-sweetened beverages and were given weekly deliveries of their choice of calorie-free options, including bottled waters, seltzers, and diet sodas. The intervention group lost weight--about 1 pound for each month of the study, while the soda drinkers' weight remained about the same.

Everybody knows that these drinks are high in calories (a 12-ounce can contains about 150 calories; the increasingly popular 20-ounce size packs 250). What people don't realize is that these calories may be particularly effective at making people fat. Perhaps because they pass through the stomach more quickly than food, "liquid calories slip past the body's weight-regulating radar system," says Ludwig. As a result, people who down sugary drinks don't feel as full as those who consume the same amount of calories in solid food.

This theory was borne out by researchers at Purdue University who, in 2000, gave 15 volunteers 450 calories a day of either soda or jelly beans for a month and then switched them for the next month, while monitoring their total calories. The candy eaters compensated for the extra calories by eating less food and maintained their weight; during the soda phase, the volunteers ate more and gained.

Liquid sugar is a problem--but the typeof sugar used in the majority of soft drinks may be making things worse. Although the research is controversial, there's evidence that the man-made high fructose corn syrup used in most sodas fails to suppress the production of ghrelin, a hormone made by the stomach that stimulates appetite.

"Unlike carbohydrates containing 100% glucose, such as the starch found in rice, potatoes, bread, and pasta, fructose doesn't seem to trigger the hormones that help you regulate appetite and fat storage," says Peter Havel, PhD, a nutrition researcher at the University of California, Davis. "So the body never gets the message to stop eating." Drink a six-pack of cola--900 calories, or about half of the total calories the average woman would need for a day--and your body feels no fuller than if you'd just swallowed water.[pagebreak]

Stop Drinking Soda Reason #2: Insulin Guzzler

Drinking soda not only contributes to making people fat, but it also stresses the body's ability to process sugar. Some scientists now suspect that the sweet stuff may help explain why the number of Americans with type 2 diabetes has tripled from 6.6 million in 1980 to 20.8 million today.

In a study published in 2004, researchers from Brigham and Women's Hospital in Boston and Harvard Medical School analyzed data from the Nurses' Health Study II, an ongoing trial tracking the health of more than 51,000 women. None of the participants had diabetes at the onset of the study in 1991. Over the following 8 years, 741 women were diagnosed with the disease. Researchers found that women who drank one or more sugary drinks a day gained more weight and were 83% more likely to develop type 2 diabetes than those who imbibed less than once a month.

"Anything that promotes weight gain increases the risk of diabetes," explains Ludwig of Children's Hospital Boston, one of the researchers. "But rapidly absorbed carbohydrates like high fructose corn syrup put more strain on insulin-producing cells than other foods." When sugar enters the bloodstream quickly, the pancreas has to secrete large amounts of insulin for the body to process it. Some scientists believe that the unceasing demands that a soda habit places on the pancreas may ultimately leave it unable to keep up with the body's need for insulin. Also, insulin itself becomes less effective at processing sugar; both conditions contribute to the risk of developing diabetes.

Interestingly, women who consumed a lot of fruit juice--which is high in natural fructose--were not at increased risk of diabetes, leading researchers to speculate that naturally occurring sugars may have different metabolic effects than added sugars. They also speculate that vitamins, minerals, fiber, and phytochemicals in fruit juices may have a protective effect against weight gain and diabetes, counterbalancing the adverse effects of sugar.

Stop Drinking Soda Reason #3: Tooth Robber

Sipping on cola is like bathing your mouth in corrosive acid. "Soda eats up and dissolves the tooth enamel," says Poonam Jain, director of community dentistry at Southern Illinois University School of Dental Medicine.

In a series of studies, Jain tested various sodas by measuring their pH--an indication of acidity. Battery acid, for example, has a pH of 1; water scores a 7. Jain found that sugar-sweetened sodas came in at about 2.5, while diet sodas scored 3.2. "The acidity can dissolve the mineral content of the enamel, making the teeth weaker, more sensitive, and more susceptible to decay," says Jain. Soda's acidity makes it even worse for teeth than the solid sugar found in candy. By eroding the enamel, soda speeds up the decay process, making it easier for bacteria to enter the teeth.

Savoring soda slowly may damage teeth more than gulping it down, Jain says. "As soon as you take a sip, it acidifies the saliva, which the body then works to neutralize." If you gulp the whole can, the saliva will return to normal in 20 minutes. "But people don't drink soda that way. They take sips over an hour or an hour and a half, and the mouth stays acidic the entire time. This is particularly an issue for people who drink several sodas a day, because they never give their saliva a chance to neutralize," she says.

Several studies, including a University of Michigan analysis of dental checkup data from the Third National Health and Nutrition Examination Survey, confirm that adults who drink three or more sodas a day have up to 62% more decayed, missing, and filled teeth than those who drink less.[pagebreak]

Stop Drinking Soda Reason #4: Bone Wrecker

In the 1950s, children drank 3 cups of milk for every 1 cup of sugary drinks. Today that ratio is reversed: 3 cups of sugary drinks for every cup of milk. Tellingly, osteoporosis is a major health threat for 44 million Americans. Most experts now say that the real culprit is soda's displacement of milk in the diet, though some scientists believe that the acidity of colas may be weakening bones by promoting the loss of calcium.

Whatever the causes of bone loss, the group that stands to suffer the most harm is adolescent girls. In a study of 460 high schoolers in 2000, research at the Harvard School of Public Health found that girls who drank carbonated soft drinks were three times as likely to break their arms and legs as those who consumed other drinks.

Dark drinks such as Coca-Cola, Pepsi, and Dr Pepper seemed to be even more dangerous than fruit-flavored sodas like Sprite: Girls who downed colas were five times as likely to break arms and legs in their teen years as girls who abstained from carbonated beverages. Grace Wyshak, PhD, a biostatistician and the study's lead researcher, believes something in colas is interfering with the body's ability to use calcium. This is a big problem, she says, "because girls will be more susceptible to fractures later in life if they don't acquire optimal bone mass in adolescence."

Drinking Soda Solutions

Obesity. Diabetes. Osteoporosis. Tooth decay. The innocent image of '50s teens sipping soda at the local malt shop is on the wane. And while America seems to be waking up to the corrosive effects of soft drinks--sales dipped 7% from 1998 to 2004--it appears sodas are being pushed aside by equally sugary competitors like sports and juice drinks.

Despite lower sales, the soft drink industry insists the studies aren't convincing enough to suggest that soft drinks are contributing to obesity or any other disease. Researchers haven't proven that "one single food or beverage causes obesity," says Richard Adamson, PhD, senior scientific consultant to the American Beverage Association.

Still, recent efforts to keep sugar-sweetened sodas out of schools signify that some government officials are concerned enough to at least try to make soda less accessible to kids. School districts in New York City, Los Angeles, and Philadelphia have banned soft drinks from schools. And in a historic agreement with health advocates, Coca-Cola Co., PepsiCo, and Cadbury Schweppes announced in May that they plan to voluntarily end the sale of nearly all sodas in school vending machines and cafeterias by 2010. They promise to sell only water, unsweetened juice, and milk to elementary and middle schools; juice drinks, sports drinks, and diet sodas will be permitted only in high schools.

Health advocates are pleased by this cascade of initiatives designed to rescue America's increasingly overweight youth, but they fear too little is being done for the rest of us who are still pounding back 18 ounces of the stuff every day. "We'd like to see more government action, like taxes on soda and other sweetened drinks, and calorie labeling in restaurants so patrons know just how much they're consuming in those supersized drink containers," says Michael Jacobson, PhD, executive director of the Center for Science in the Public Interest, a consumer advocacy group in Washington, DC, that pressured beverage makers to the bargaining table with the threat of a lawsuit.

Jacobson dreams of a day when you'll pick up a six-pack of soda and each can will have a different cautionary message. One might warn that sweetened drinks can lead to obesity. Another might urge consumers to drink water or calorie-free sodas instead of sweetened drinks. A third might alert people to the link between soda consumption and osteoporosis.

But why wait for the government to confirm and legislate what the best nutrition minds already know? Sugared drinks, in their myriad forms, are an unnecessary and potentially detrimental addition to the American diet. And there is no shortage of perfectly healthy alternatives. C'mon, America, it's time to kick the soda habit.[pagebreak]

Our changing habits

Americans used to drink more than twice as much milk as soda; not anymore

Source: American Journal Of Preventive Medicine

Milk

8% daily calories 1978; 5% daily calories 2001

Soda

3% daily calories 1978; 7% daily calories 2001

The Diet Dilemma

Almost a third of all carbonated beverages sold in the United States are diet. But are these drinks really any healthier? Not particularly, says Michael Jacobson, PhD, executive director of the Center for Science in the Public Interest. "A can of diet soda doesn't contain 10 teaspoons of sugar, but it has its own problems: caffeine, which is a mildly addictive substance; acids that promote dental erosion; and artificial sweeteners, which raise some small safety questions," he says.

Diet sodas may not even help ward off weight gain. When researchers at the University of Texas Health Science Center examined data from the San Antonio Heart Study, a 25-year look at health habits, study author Sharon Fowler, an epidemiologist at the center, found that the more diet sodas a person drank, the greater his or her risk of becoming overweight.

An explanation may come via a recent animal study by researchers at Purdue University. They found that artificial sweeteners can interfere with the body's natural ability to regulate calorie intake. This could mean people who consume artificially sweetened items are more likely to overindulge.

Most scientists agree that when it comes to bone health, diet drinks are just as harmful as sugar-sweetened ones. Because diet soda lovers tend to substitute these drinks for milk, they're at higher risk of calcium deficiency.

Sugar-free drinks aren't healthier for your pearly whites, either. "There's a myth that diet soda is okay because it's not sugary," says Poonam Jain, director of community dentistry at Southern Illinois University School of Dental Medicine. Her research revealed that diet drinks were nearly as acidic as regular; thus they, too, can erode tooth enamel and lead to tooth decay.